WITH TARGET_CONV AS (
   SELECT *
   FROM CONVENIENCE
   WHERE SURVEY_YEAR = 2019 AND KIND_CODE = '100' 
),
CONV_MEDIAN AS (
    SELECT
        TOTAL_VALUE
        ,ROW_NUMBER() OVER (PARTITION BY KIND_CODE ORDER BY TOTAL_VALUE DESC) AS ROW_ID
        ,(  SELECT COUNT(1)
            FROM TARGET_CONV
        ) AS TOTAL_COUNT
    FROM TARGET_CONV
)
SELECT
    ROUND(AVG(TOTAL_VALUE)) AS SA_MEDIAN
FROM CONV_MEDIAN
WHERE ROW_ID BETWEEN TOTAL_COUNT/2.0 AND TOTAL_COUNT/2.0 + 1;